Veneer redrying press and method of operation



y ,;1967 J. D. WHITLOW 3,318,014

VENEER REDRYING PRESS AND METHOD OF OPERATION Filed March 29, 1965 E552; [111. [31 1 Pi- :z ii, .20 3| 32 FIG.3

JAMES D. WHITLOW attorney '7 FIG.4

United States Patent 3,318,014 VENEER REDRYING PRESS AND METHOD OF OPERATION James D. Whitlow, Greensboro, N.C., assignor to Dependable Machine Company, Inc., Greensboro, N.C.,

a corporation of North Carolina Filed Mar. 29, 1965, Ser. No. 443,246 13 Claims. (Cl. 34-133) This invention relates to a veneer redrying press and method for conditioning sheets of veneer fiitches and relates more particularly to an apparatus that will allow the immediate and time saving exhaustion of pressurized steam within that press.

A variety of industries, particularly furniture manufacturers, require substantial quantities of veneer flitches from which to laminate or finalize their marketed product or commodity, and this demand has made it necessary that large and eflicient machines for conditioning these flitches be developed and manufactured along with control equipment for their expeditious use. The conventional operation of such a veneer conditioning machine requires the insertion of a large number of recently prepared and moisture-containing fiitches between a plurality of horizontal platens or pressing surfaces so that these surfaces might be moved together to compress and demoisturize the inserted flitches. As an additional part of the operation, the redrying presses usually are equipped with heating devices for raising the temperature of these platens to the extent that the drying operation is expeditiously accomplished.

Control mechanisms for these presses usually establish a procedure of operation so that the platens may be actuated and moved together to initiate the compressing and drying operation, held in this conditioning position until sufiicient moisture has been removed and straightening has been effected, and then returned to their original open position for the subsequent removal of the conditioned or treated flitches. During the early stages of the development of these machines, it was found that when the platens were closed tocompress retained materials and were held in this closed position, their surfaces became essentially sealed against the contained veneer flitches, and if the platens were maintained in this position for any length of time, the moisture from within the fiitches was flashed into steam developing a high pressure zone between platens. In order to alleviate the dangers accompanying such a pressurized concentration of steam, it was found necessary, during the course of one compression and heating cycle, to expand the platens several times to breathe or to exhaust the zones between platens on the machine to allow the removal of the trapped steam.

Unfortunately, to perform this breathing or steam exhausting operation while using the machines conventional and efficient double action cylinder, required the opening of the platens to their original separated and fully open position, a position entirely unnecessary as far as completely removing the trapped steam from within, but completely essential because of the particular structural limitations of the cylinder, piston and platen arrangement.

displacing pistons to the fully open position since each of the platens were linked together and would move from the closed position only when the preceding platen nearest the pistons was fully displaced to its own fully open position. Obviously if all platens were merely displaced minutely from their closed positions thus breaking the seal with the contained flitches, there would be 'a sufiicient opening for the escape of the pressurized steam to avoid platen distortion. As soon as the steam was In order to provide uniform openings between all adjoining fiitches, it was necessary to move the platenevacuated, the platens could be closed again for the continuation of the conditioning operation.

The present improvement utilizes the above principle and incorporates the use of a plurality of quick release mechanisms to permit the platens to separate minutely or part the platens sufficiently for steam evacuation and thus avoids the lengthy operation of recycling and separating these platens to the fully open position as in loading. As the pressure exerted by the platen-displacing pistons against the platens forcing them together is released, there is an immediate platen separation movement to accomplish steam exhaust. The operation is eifected by a relay that merely releases the pressure on one side of the double acting cylinder, and then this cylinder is reactivated on its same pressure exerting side so as immediately to force the platens together again and resume operation at the normal temperature and pressure level.

it has been found that the installation and use of the quick release mechanism of this invention results in a savings of approximately'one and one-half minutes out of the normally required nine minute cycle when such a mechanism is not used.

Accordingly, an object of this invention is to provide a quick release or breathing mechanism for use with a veneer redrying press to provide a considerable time savings in the normal operation cycle of a veneer redrying press.

Another object of this invention is to provide a release or breathing mechanism for a veneer redrying press that will avoid recycling the press during each operating cycle to allow the evacuation of highly pressurized steam from between platens so as to save excessive machine wear from this additionally required conventional operation.

A further object of this invention is to provide a quick release or breathing mechanism for a veneer redrying press that is simple in operation, basic in construction, readily accessible for maintenance and economical in cost.

Other objects of this novel release assembly will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which like characters of reference designate corresponding parts throughout the several views, and wherein:

FIG. 1 is a front perspective view of a veneer redrying press incorporating a plurality of quick release assemblies attached to the horizontal platens;

FIG. 2 is an enlarged side elevational fragmentary view of one end of the redrying press showing a release assembly attached to the platens in the platen normally open position;

FIG. 3 is an enlarged side elevational fragmentary view of one end of the redry press showing a release assembly attached to the platens in the platen closed position; and

FIG. 4 is an enlarged side elevational fragmentary view showing one end of the redry press with a release assembly attached and the press in its partially cracked or breathing position.

Referring to the drawing and particularly to FIGS. 1 and 2, there is illustrated a veneer redrying press 10 of conventional construction with certain features omitted and including a framework superstructure 11 with a plurality of downwardly extending or depending vertical legs 12 that are laterally spaced-apart from each other on one side of the press and also on the opposite side of the press to accommodate a plurality of vertically displaceable horizontal platens 13, 14, 15, 16, 17 and 18 that are guidably supported for vertical displacement within the framework depending legs 12. The upper platen 13 is suitably secured to the upper bolster 19 with the lower 'platen 18 being securely fastened to the lower bolster 20.

Platens 13 and 13 remain fixed to their respective bolsters.

Veneer flitch-receiving compartments 21, 22, 23, 24 and 25 are provided between the platens 13 through 18 to retain the flitches or veneer strips 26 in stacked relationship when the platens are in the open or parted positions illustrated in FIGS. 1 and 2.

Each of the platen 13 through 18 is provided with longitudinally extending coils or tubes (not shown) through which a heating medium may be circulated continuously to provide the requisite heat for drying or ouring the stacked veneer strips or flitches 26 upon downward displacement of the platens upon actuation of the hydraulically operated pistons or rams 27 that extend from the hydraulic cylinders 28 mounted onto the superstructure of the framework 11. The hydraulic pressure lines are omitted as such lines and the control means are conventional.

Presently hydraulically operated veneer redrying presses employ a linkage connection which will sequentially raise each of the platens as the uppermost platen is elevated and in turn will raise the next succeeding platen in the series accounting for an appreciable amount of time in the sequential elevation of the series of platens to exhaust the steam and vent any pressures generated during the heating cycle when the flitches 26 are compressed and subjected to the elevated temperatures transmitted by the heating medium flowing through the platens. The disadvantage in the prior art devices permitted the exhaustion or breathing of one compartment at a time, in series, but the cycle would be completed only after the last chamber would be vented or exhausted. The disadvantage arising from the time delay in exhausting the last chamber resulted in an extended cycle and reduced roduction.

To overcome the disadvantages of the conventional veneer redrying presses, a series of quick release mechanisms or assemblies 29 are supported in spaced relation along the sides of the platens enabling the platens to separate or part expeditiously upon release of hydraulic pressure exerted by the pistons 27 on the upper bolster 19 which pressure will displace the platens downwardly sequentially into the fully compressed condition illustrated in FIG. 3.

Each of the quick release mechanisms or assemblies 29 is provided with a guide bar supporting bracket 30 secured to the upper platen '13 and a lower guide rod supporting bracket 31 securely supported onthe lower platen 18 with the lower bracket 31 being provided with a guide rod opening for slidably receiving the guide rod 32 therein. The upper end of the guide rod 32 is securely fastened to the upper brackets 30 by a suitable setscrew or pin 33.

A series of intermediate guide bar brackets or shoulders 34, 35, 36 and 37 is securely fastened to the sides of the platens and vertically aligned to receive the guide rod 32 through openings provided in the shoulders. Platen separating and supporting helical spring members 38, 39, 40 and 41 are positioned between their respective intermediate guide bar brackets or shoulders as shown in FIGS. 1 and 2. In the loading or de-activated condition shown in FIGS. 1 and 2, the helical spring members 38 through 41 are shown in the extended re laXed condition separating or parting the platens each from the other forming the flitch-receiving compartments 21 through 25 for receiving and sandwiching the flitches 26 therein.

The veneer strips or flitches 26 may be moist or have retained moisture upon being introduced into the flitchreceiving compartments 21 through 25 and the flitches may be in a distorted, sinuous or warped condition prior to being subjected to high temperature and pressure in the veneer redrying press 10. Upon actuation or supply of hydraulic pressure from the hydraulic system (not shown) the pistons 27 will exert a downward pressure on the upper bolster 19 urging it and the platen 13 downwardly into engagement with the intermediate stack of flitches 26 in compartment 21. It has been found desirable to omit the helical springs in some veneer redrying presses from between the platen 13 and the platen 14. Further displacement of the pistons 27 will urge the platens 14, 15, 16 and 17 downwardly against the biasing action of the helical springs 38 through 41 until the condition of compression is reached as illustrated in FIG. 3 in which the stacks of flitches 26 are compressed and straightened in a rectilinear fashion. The guide rod 32 extends or slides downwardly through the lower guide rod bracket 31 and the springs are compressed substantially depending upon the depth of flitches 26 retained in each of the flitch-receiving compartments.

The requisite heat and pressure are applied while the platens are in the condition shown in FIG. 3 to straighten and dry the flitches in stacked condition. Presently a time cycle of from approximately nine to nine and onehalf minutes is utilized without the quick release assembly or mechanism which necessitates the sequential re' lease of each platen. In the utilization of the quick release assemblies 29, the platens may be parted or separated momentarily and instantaneously to permit breathing and exhaustion of pressurized'steam and vapor. It will be noted in FIG. 4 that platens 13 through 16 are elevated partially and uniformly to permit the breathing or exhaustion in the cycle before applying a compression force again. It has been found that approximately one minute to one and one-half minutes may be saved from the conventional cycle of approximately nine to nine and one-half minutes by reason of the instantaneous and simultaneous opening of each of the compartments 21 through 25 over the prior sequential opening of each of the compartments. It will be readily apparent that immediately after the breathing or exhaustion cycle as depicted in FIG. 4, immediate compression may be effected for a continued compression cycle, and this alternate procedure may be repeated for as many times during one cycle as may be necessary depending upon the moisture content in the flitches and the thickness of the flitches.

The closed or sandwiched position illustrated in FIG. 3 will cause or generate, upon the introduction of the high temperature fluid in the platens, the build-up of pressure generated when the moisture flashes into steam since the bond between the platens and the flitches is virtually a sealed chamber.

It will be understood that for the purpose of this disclosure, a complete cycle commences when the flitches are introduced for the first time between platens and ultimately removed after being subjected to one or more heating and compressing operations. While only one preferred embodiment has been disclosed in which a plurality of aligned or stacked helical spring members is utilized on a single guide rod, alternative resilient or biasing means may be utilized for the purpose of simultaneously parting or separating the stacked platens. It is contemplated that leaf springs may also be employed and will be flexed during the closed switch conditioning position enabling the springs to be sufliciently flexed whereby upon release of the compressive action of the pistons, the platens may be separated, at least partially, to the flitch breathing or exhausting position as illustrated in FIG. 4.

It will be readily apparent that the number of spring members as well as the number of quick release assemblies or mechanisms may vary with the number of platens and that various modifications are contemplated within the scope of the appended claims.

What is claimed is:

1. In an hydraulically operated veneer flitch redrying press having a frame movably supporting a plurality of horizontal heated platens vertically displaceable between limits, said platens movable from an open position to receive stacked flitches between platens to a closed flitchcompressing and drying position, and hydraulic pistons for moving the platens from an open to a closed position and back again, the improvement for selectively and rapidly separating the platens to remove pressurized steam trapped therebetween comprising a plurality of quick release assemblies common to said plural platens, each of said assemblies having a guide rod, helical springs guidably supported and compressible on said rod and a shoulder mounted on each of said platens for separating said springs from each other whereby upon pressure release said springs expand and will separate the platens.

2. In a veneer redrying press having a frame movably supporting a plurality of stacked and heated platens, cylinders containing platen-displacing pistons secured to said frame, said platens movable by said pistons from a separated open fiitch-receiving position to a closed fiitch conditioning position, said open position permitting a quantity of veneer flitches to be received therebetween for compressing and drying when said platens are moved to said closed position and means for actuating said platendisplacing pistons to move said platens from said open to said closed position and back again, the improvement for rapidly separating the platens subsequent to compressing and drying flitches to remove pressurized steam comprising a plurality of quick release means having a plurality of slidably secured guide rods common to said platens, and biasing means carried by said rods and position for rapidly separating said platens uniformly upon pressure release.

3. An apparatus as defined in claim 2 and in which the biasing means is a plurality of helical springs guidably supported on said rod and for individually separating said platens.

4. In an hydraulically operated veneer redrying press having a frame movably supporting a plurality of stacked and heated platens from an open fiitch receiving and platen separated position to a closed fiitch conditioning position, said open position allowing said platens to receive stacked veneer flitches therebetween and said closed position conditioning said flitches by compressing and removing moisture therefrom the lowermost platen being stationary and the remaining platens being movably positioned therefrom, and pressure means for moving said platens from said open to said closed position and back again, the improvement with said press for rapidly and independently separating the platens subsequent to compressing and drying veneers to allow steam escape comprising a plurality of slidably mounted guide rods common to said platens, each of said rods carrying a plurality of helical springs individually positioned to separate and resiliently urge said remaining platens individually and independently apart from said stationary platen and from each other, said springs being compressed when said platens are in said closed position and expanded immediately to urge said platens apart when said pressure means is de-activated.

5. In an hydraulically operated veneer redrying press having a frame, a plurality of horizontal and parallel heated platens movably supported by said frame, said platens removable from an open fiitch-receiving position to a closed fiitch compressing position, said open position locating said platens to receive a quantity of veneer flitches therebetween and said closed position permitting said flitches to be heated and compressed between said platens to remove moisture therefrom, and pressure means for moving said platens from said open to said closed position and back again, the improvement for rapidly separating the platens subsequent to compressing and drying flitches to release pressurized steam comprising a plurality of guide rods slidably supported and common to said platens, helical springs guidably mounted on each of said rods yieldably biasing each of said platens apart, said springs compressing when said platens are in the press closed position and expanding immediately to urge said platens apart for steam escape when said pressure means is de-activated.

6. In an hydraulically operated veneer redrying press having a plurality of horizontal platens vertically displaceable between limits to receive veneer flitches between platens, and hydraulically operated pistons for displacing the platens compressing the flitches stacked therebetween, the improvement for rapidly separating the platens subsequent to compressing flitches comprising a plurality of spaced-apart quick release means secured to separate adjacent platens, each of said means having a guide rod, springs guidably supported on said rod, means on said platens for separating said springs from each other whereby upon pressure release said springs will separate the platens exposing the veneer flitches sandwiched between platens.

7. In an hydraulically operated plywood press having a plurality of horizontal plywood press platens vertically displaceable between limits to receive veneer strips sandwiched between platens and hydraulically operated pistons for displacing the platens compressing the veneers stacked between platens, the improvement for rapidly separating the platens subsequent to compressing veneers comprising a plurality of spaced-apart quick release means secured to separate adjacent platens, each of said means having a guide rod, helical springs guidably supported on said rod, means on said platens for separating said springs from each other whereby upon pressure release the springs will separate the platens.

8. In an hydraulically operated veneer press having a plurality of stacked horizontal heated platens vertically displaceable and forming a veneer-receiving chamber between platens for drying and compressing veneer strips, the improvement for separating the platens rapidly after the application of heat and pressure to release moisture and vapor between platens comprising a plurality of spaced-apart quick release means mounted on said platens, each of said means having a vertical guide bar extending transversely across said platens, means on said platens for guidably supporting said guide bar, a plurality of helical springs axially aligned on said guide bar with at least one of said springs positioned between said guide rod-supporting means on adjacent platens whereby upon release of pressure for compressing the veneer strips between platens the platen-separating means will part the platens enabling moisture to be released rapidly from the veneer strips and between platens.

9. In an hydraulically operated veneer press having a plurality of stacked horizontal heated platens vertically displaceable between limits and forming a veneer-receiving chamber between platens for drying and compressing veneer strips, the improvement for separating the platens rapidly after the application of heat and pressure to release moisture and vapor between platens comprising a plurality of spaced-apart quick release means in juxtaposition to said platens, each of said means having resilient means for yieldably biasing said platens apart whereby upon presure release for compressing veneer strips said resilient means will separate the platens.

10. In an hydraulically operated veneer press having a plurality of stacked horizontal heated platens vertically displaceable and forming a veneer-receiving chamber between platens for drying and compressing veneer strips, the improvement for separating the platens rapidly after the application of heat and pressure to release moisture and vapor between platens comprising a plurality of spaced-apart quick release assemblies mounted in juxtaposition to said platens for contact therewith, each of said assemblies having guide means common to said platens and resilient means operable with said platens whereby upon release of pressure for compressing the veneer strips between platens the resilient means will separate the platens.

11. In an hydraulically operated veneer fiitch redrying press having a frame movably supporting a plurality of horizontal heated platens vertically displaceable between limits, said platens movable from an open position to receive stacked flitches between platens to a closed flitchcompressing and drying position, and hydraulic pistons for moving the platens from an open to a closed position and back again, the improvement for selectively and rapidly separating the platens to remove pressurized steam trapped therebetween comprising a plurality of quick release assemblies common to said plural platens, each of said assemblies having guide means, helical springs vguidably supported and compressible on said guide means and means on each of said platens for separating said springs from each other whereby upon pressure release said springs expand and will separate the platens.

12. In an hydraulically operated veneer redrying press having a plurality of horizontal platens vertically displaceable between limits to receive veneer flitches between platens, and hydraulically operated pistons for displacing the platens compressing the flitches stacked therebetween, the improvement for rapidly separating the platens subsequent to compressing flitches comprising :a plurality of spaced-apart platen quick release assemblies in juxtaposition with said platens, each of said assemblies having guide means for maintaining said platens in vertical alignment during platen displacement, and resilient means contiguous said platens whereby upon pressure release the resilient means will separate the platens for heat and steam escape.

13. The method of conditioning veneer flitches in a 30 8 veneer redrying press having a plurality of horizontal heated platens for receiving veneer flitches vertically movable between limits and compressible helical springs separating the platens comprising the steps of: placing stacks of flitches to be conditioned between the horizontal separated and heated press platens; compressing the flitches by moving the platens together and compressing the separating helical springs; drying the flitches by maintaining the heated platens together for preselected period 0 of time; releasing compression on the helical springs to allow steam escape so that the compressed springs instantaneously and uniformly separate the platens to allow steam escape; compressing and heating the flitches again by moving the platens together; and quickly releasing, separating and cooling the platens to allow the removal of stacked flitches therebetween.

References Cited by the Examiner UNITED STATES PATENTS 435,309 8/1890 Jones 34l43 578,110 3/1897 Mallett 34-144 674,342 5/1901 Nichols 34l44 X 1,939,014 12/1933 L'ocher 34144 2,558,796 7/1951 Tapper 34144 X 2,586,474 2/1952 Moore 34l44 X FREDERICK L. MATTESON, 111., Primary Examiner.

JOHN J. CAMBY, Examiner. 

9. IN AN HYDRAULICALLY OPERATED VENEER PRESS HAVING A PLURALITY OF STACKED HORIZONTAL HEATED PLATENS VERTICALLY DISPLACEABLE BETWEEN LIMITS AND FORMING A VENEER-RECEIVING CHAMBER BETWEEN PLATENS FOR DRYING AND COMPRESSING VENEER STRIPS, THE IMPROVEMENT FOR SEPARATING THE PLATENS RAPIDLY AFTER THE APPLICATION OF HEAT AND PRESSURE TO RELEASE MOISTURE AND VAPOR BETWEEN PLATENS COMPRISING A PLURALITY OF SPACED-APART QUICK RELEASE MEANS IN JUXTAPOSITION TO SAID PLATENS, EACH OF SAID MEANS HAVING RESILIENT MEANS FOR YIELDABLY BIASING SAID PLATENS APART WHEREBY UPON PRESSURE RELEASE FOR COMPRESSING VENEER STRIPS SAID RESILIENT MEANS WILL SEPARATE THE PLATENS. 